The Bosman ruling of 1995 increased the gap between the clubs of the top 4 European leagues (England, Germany, Italy, and Spain) and the rest of the European clubs. This law, combined with the increasing business approach to football, drastically changed the balance of power between the clubs in Europe.
Of the 23 Champions League titles won after the Bosman ruling (from 1996-1997 and 2018-2019), 22 of them (96%) were won by a club of the top 4 leagues (11 by Spanish clubs, 5 by English clubs, 3 by Italian clubs and 3 by German clubs). The only club outside of the Big 4 to have won the Champions League, post the Bosman ruling era, is FC Porto in 2004. Among the 46 teams that reached the final, 44 teams (96%) were among the Big 4 leagues (15 from Spain, 12 from England, 9 from Italy and 8 from Germany). The only final with teams outside the Big 4 leagues, was the 2004 final between FC Porto (Portugal) and AS Monaco (France). The results in the 23 seasons before the ruling was adopted (1973/74 to 1995/96) were much different. During these years, 6 clubs from leagues outside the Big 4 managed to win the competition: Steaua Bucharest (Romania) in 1986, FC Porto (Portugal) in 1987, PSV Eindhoven (Netherlands) in 1988, Red Star Belgrade (Serbia) in 1991, Olympique Marseille (France) in 1993 and Ajax Amsterdam (Netherlands) in 1995. The top 4 leagues won the other 17 editions (74%). 34 of the 46 finalists were clubs from the top 4 leagues (74%). 12 finalists were clubs outside the Big 4, including Club Bruges (Belgium) in 1978 and Malmo FF (Sweden) in 1979. Thus, in the period before the Bosman ruling, the major European competition was more open and clubs from outside the Big 4 regularly played a major role and went on to win the competition. The concentration of the top European players in the clubs of the Big 4 after the Bosman ruling made it almost impossible to have a winner from a club outside the Big 4.
Before the Bosman ruling, the top players from leagues such as Portugal, Netherlands, Belgium, Sweden, Romania, Croatia, Serbia were almost all playing for a domestic club. That made surprises possible in the Champions League, with the presence of a specific quality generation from a country. This is how teams from these countries succeeded in winning the competition or at least reach the final on several occasions. After the Bosman ruling, the best players of the continent are now playing for the Big 4 leagues clubs. This is how, for example, almost all the first 11 of national teams like Holland, Croatia or Belgium play their club football for the top teams in Europe. The margin for a surprise winner in the Champions League is now very small, if not non-existent. France is also very significant example. Despite winning 2 World Cups in the last 22 years, the French clubs are failing to repeat the successes of the national team as all the best players play for either Germany, England, Spain or Italy.
Parallel to the Bosman ruling, the constant evolution of the competition’s format has been of an increasing advantage to the teams of the 4 major leagues. First, in 2002, UEFA added a qualification ticket to the runners-up of the 4 major leagues, and in 2016 these leagues were rewarded 4 places in the competition for each of them. In addition to the fact that they were already the best in quality, they had an important advantage in quantity at the beginning of the competition. Thus, from the 32 teams that start the group phase of the Champions League now, 50% of them come from Spain, Italy, Germany and England. This evolution is also the result of the bigger financial stakes that have progressively accompanied the football industry. The gap between the Big 4 and the rest of Europe should increase with the rise of the revenues from TV rights, stadiums and merchandising. 60% of the UEFA’s TV rights revenues come from the Big 5 countries (England, Germany, Italy, Spain and France). Thus, it’s very likely that UEFA will constantly evolve its format to benefit these countries and skew the competition results even more in favor of the big leagues.